Draft gear



J. M. HALL DRAFT GEAR Dec. 22, 1931.

4 Sheets-Sheet Filed Aug. 5 1925 J. M. HALL DRAFT GEAR Dec. 22, 1931.

Filed Aug. 31, 1925 4 Sheets-Sheet 2 Dec. 22, 1931. J M HALL 1,837,816

DRAFT GEAR Filed Aug. 31, 1923 4 Sheets-Sheet 3 j li'y; 6.

DRAFT GEAR Filed Aug. 31, 1925 4 Sheets-Sheet 4 Patented Dec. 22 1931 UNITED STATES I PATENT OFFICE JOSEPH M. HALL, OF HAMILTON, ONTARIO, CANADA, ASSIGNOR TO UNIVERSAL DRAFT j GEAR ATTACHMENT 00., A CORPORATION OF ILLINOIS DRAFT, GEAR Application filed August 31,1923. Serial No. 660,351.

This invention relates to a draft gear or shock absorber which is more partlcularly designed for use on railway cars although the same may also be used to advantage in other installations. Its object is to provide a con struction which is compact and furnishes the maximum cushioning effect to resist pulling and buffing stresses and toacc'cmplish this by means which in their preferred form comprise a single spring for setting up a variable amount of friction, and a plurality of springs for effecting a release of the draft gear when a sufficient amount of the buffing orpulling force or load has been removed.

In the accompanying drawings:

Figure l is horizontal longitudinal section of my improved draft gear showing the same in a fully released or open position. Figure 9. is a similar view in a fully closed position. Figures 3 and 4 are vertical longitudinal sections taken on the correspondingly numbered lines in Figs. 1 and 2, res )ectively. Figure 5 is a plan view of one of the friction plates. Figures 6 and 7 are vertical transverse sections taken on the corresponding numbered lines in Fig. 1. FigureS is afragmentary horizontal transverse section on an enlarged scale, taken on line 8-8, Fig. 2. Figure 9 is a horizontal longitudinal section "on line 9-9, Fig. 8. Figure 10 is a fragmentary vertical section, on an enlarged scale, in line l01'0, Fig. 7. Figures 11 and 12 are perspective views of one of the wedge plates or shoes and one of the wedge rings or surrounding thrust members forming part of thls draft gear.

Figure 13 is a fragmentary longitudinal sectransversely between said car sills, the fol lower 23, for example, normally engaging its outer side with the draft lugs 21, and the follower 24 normally engaging its outer side with the draft lugs 22. Between the opposing inner sides of the followers are arranged a plurality of longitudinal friction plates 25 constituting two sets, the members of one set alternating with those of the other so that they are intercalated. At times these sets of friction plates are engaged, respectively at their outer ends by the followers so that they arecompelled to move longitudinally inward with the latter and at other times the outer ends of these sets of friction plates are spaced apart from the respective followers for a purpose which will presently appear. Each of these frictionplates is provided on the outer parts of their longitudinal edges with notches 26 forming inwardly facing shoulders 27 and the inner parts of these edges are cut away, as shown at 28, so that this end of each friction plate isreduced in width.

On opposite fiat sides of the outer parts of the two sets of friction plates are arranged two pairs of wedge plates or shoes 29, 30, the members of each pair being arranged transversely opposite each other and engaging their inner flat sides with the friction plates to produce a variable pressure upon the frie tion plates so that they engage each other with varying degrees of friction and thus resist relative longitudinal movement of the same accordingly. The members of each pair of wedge plates are coupled with one of the followers so as to be compelled to move" vented-by providing each of the wedge plates on its outer side with a longitudinal retaining rib 34 which engages with a notch 35 on the inner edge of the adjacent retainingiplate, as shown in Figs. 1, 2, 8, 9 and 10.

I movement of the same.

Each of the wedge plates is provided on its outer longitudinal side with an inclined or wedge face 36. Surrounding each pair of wedge plates and the intervening friction plates is a thrust member 37 of substantially ring or annular form, the bore of which is oval or elongated and forms two parallel walls 38 which extend past the longitudinal edges of the friction plates and wedge plates while thetransverse parts of each thrust member are provided with inclined or wedge faces 39 which engage with the wedge faces of the wedge plates. The inclined faces of each pair of wedge plates, andthe inclined faces of the thrust members cooperating therewith converge inwardly so that a wedg ing engagement is produced between these parts upon efiecting a relative longitudinal Lateral displacement of the wedge plates and thethrust memhers is avoided by providing each wedge plate on its outer side with a-longit-udinal retaining rib 40 which engages with a notch 41 in the adjacent inner edge portion of the certain times, coupling mean are provided which preferably consist of stop lugs 42 arranged transversely on the rear part of the longitudinal rib 40 of' each wedge plate and adapted to engage with the inner side of the companion thrust member. The numeral 43 represents a thrust spring which is of helical form and surrounds the central parts of the friction plates and the inner ends of the wedge plates and bears at its opposite ends against the opposing inner flat faces of the thrust members.

Resilient means are provided which operate constantly to move the followers outwardly or apart from each other for the purpose of releasing the draft gear. In the preferred form these means comprise a plurality of helical releasing springs 44 arranged lengthwise indiflerent places around the outer side of the thrust spring, preferably adjacent to the four corners of the followers and adapted toforce the latter apart from each other. The releasing springs may be mounted on the followers in any suitable manner but preferably,

by providing each of the retaining plates 32 at its opposite ends with inwardly facing spring seats 45 which are engaged by the adjacent ends of the releasing springs, as shown in Figs. 3 and 6.

The followers are prevented from separate with the outer sides of the followers, as best shown in Fig. 3. Y

The movement of the followers toward each" other for limiting the extent of closing of the draft gear is preferably effected by a plurality of stop members or spacers 49 having the form of tubes each of which surrounds one of the tie rods and is arranged within one of the releasing springs, and is adapted to have its opposite ends engaged by the spring seats of the followers. 1 The operation of the draft gear is as folows: 1

When the draft gear is in its fully released condition, the parts are'in the position shown in Fig. 1, in which the followers are separated until they bear against the sill stops on the car and the heads and nuts of the tie rods, the wedge plates engage their outer ends with the followers, the two sets of friction plates are drawn apart and each set is slightly sepa: rated at its outer end from the companion follower, each thrust member bears with its outer side against the inwardly facing shoulders 27 of the respective sets of friction plates.

The followers are held in this position by the combined resilience of the release and thrust springs, but the wedge plates and thrust members are held in this position by the resilience of the thrust spring which latter is under tension and throughthe medium of the wedg ing engagement of the thrust members with the wedge plates causes the latter to be pressed transversely inward and thus maintain an initial frictional engagement between the friction plates in the released position of the draft gear. I

Assuming now that one of the followers is moved toward the other, either by a pulling or pushing load or stress, the first effect is that the moved follower will travel inwardly independently of its companion set of friction plates until the slack space between this follower and set of plates has been taken up after which this follower and set of plates travel in unison to the end of the inward stroke of the same. This initial inward movement of the movable follower encounters the minimum resistance of the draft gear presented by the releasing springs, thrust spring and the frictional engagement between the friction plates. However, as one pair of wedge plates is moved inwardly, the thrust member thereon is also pressed inwardly so that the tension on the thrust spring is increased which causes boththrust members by their wedging engagement with advance toward the stationary or inactive follower, compression of the friction spring increases in the same measure and this operates to correspondingly increase the frictional engagementbetween the several thrust plates owing to the increasing effect of the wedge action of the thrust members upon the wedge plates which operates to force the latter transversely inward as the shortening of the distance, between the followers progresses.

The resistance of the thrust spring, releasing springs, and of the friction plates continues to build up in this manner until the followers engage with opposite ends of the tubular stop members 49 which operate to limit this action when the maximum effect has been reached for which the draft gear has been designed.

In this manner the shock during the pulling or bufling stresses or loads upon coupling cars or starting transportation of the same is gradually taken up or absorbed thus relieving thecars and their contents of undue jarring and possible breakage. I

When the force which has closed the gear has been sufficiently reduced, the release springs force the followers apart during a which time the friction shoes or wedge plates of the two followers are also dragged apart. As the wedge plates recede, the surrounding thrust members retract with the wedge plates due to the pressure of the thrust spring against them. During the initial part of this return movement of the thrust members, they do not affect the position of the friction plates, but at the end of this movement the returning thrust member engages with the shoulders 27 of the corresponding friction plates so that the latter are thereafter compelled to move backwardly with the respective thrust member, wedge members and follower and the other set of friction plates is dragged frictionally in the same direction until the shoulders 27 of the same also engage the companion thrust member.

When the friction shoes or wedge plates have sufliciently relieved the pressure on the friction plates, the pressure of the thrust spring against the thrust members causes the friction plates to be moved back into their open position and the inward pressure against the same to be reduced accordingly for restoring the frictional engagement and resistance of the friction plates to the minimum at which the gear has been set.

By providing the wedge plates with stops 42 for engagement with the inner side of the thrust members,it .is only possible to move one set of wedge plates outwardly independently of the companion thrust member .until the stops engage the respective thrust member, after which these stops compel this thrust member to travel outwardly, thus en'- suring releasing the pressure of the friction plates against each other at :both ends of the draft gear.

Vhen the followers of the draft gearlare brought to a standstill by sudden Contact with the draft lugs of the car frame or body, the release movement of the friction plates is arrested,'due to the action of the thrust spring on the thrust members, which latter in turn force the wedge plates against the friction plates until the frictional resistance is equal to the force of the thrust spring.

Instead of providing the wedge plates and thrust members with inclined faces which engage directly with each other, as shown in Figs. 1 and 2, the optional organization shown in Fig. 13 may be employed consisting of a roller 51 interposed between curved surfaces 52, 53 on the wedge plate 54 and the thrust member 55, whereby the friction between these members is reduced and the capacity of the draft gear is'increased.

I claim as my invention 1. A draft gear comprising a plurality of sets of intercalated friction plates, followers adapted to engage the outer ends of said sets of plates, wedge plates movable lengthwise with said followers and engaging with the outer sides of said friction plates, thrust mem-i. bers having a wedging engagement with said wedge plates, a thrust spring surrounding said friction plates and engaging said thrust members, releasing spring means interposed between said followers andarranged outside. of said thrust spring, a tie rodextending through said releasing spring means and connecting said followers, a stop member ar-' ranged within said releasing spring means and around said tie rod for limiting the move-' ment of said followers toward each other and means for returning the plates to normal or released position. I

2. A draft gear comprising a plurality of sets of intercalated friction plates, followers adapted to engage against opposite outer ends of said sets of plates, a plurality of pairs of wedge plates engaging their inner longitudinal sides with said friction plates and provided on their outer longitudinal sides with inclined faces andcoupled respectively with said followersso as to move lengthwise therewith, thrust members surrounding said pairs of wedge plates and each thrust member provided with inclined faces engaging with the. inclined faces of one pair of wedge plates, a thrust spring surrounding said friction plates and engaging its opposite ends with said thrust members and operating constantly to force the same apartand means for return-t ing the plates to normal or released position.

3. A draft gear comprising a plurality of sets of intercalated flat friction plates, followers adapted to engage against opposite outer ends ofsaid sets of plates, a plurality of I pairs of wedge plates engaging their inner engaging with the inclined faces of one pair of wedge plates, a thrust spring surrounding said friction plates and engaging its opposite ends with said thrust members and operating constantly to force the same apart, releasing spring means arranged outside of said thrust spring and operating to separate said followers and means for returning the plates to normal or released position.

4. A draft gear comprising a plurality of sets of intercalated friction plates, followers adapted to engage against opposite outer ends of said sets of plates, a plurality of pairs of wedge plates engaging their inner longitudinal sides with said friction plates and provided on their, outer longitudinal sides withinclined faces'and coupled, respectively, with said followers so as to move lengthwise therewith, thrust members surrounding said pairs of wedge plates and each thrust member provided with inclined faces engaging with the inclined faces of one pair of wedge plates, a thrust spring surrounding said friction plates and engaging its opposite ends with said thrust members and operating constantlyto force the same apart, means for positively coupling each of said wedge plates with its thrust members during a part of the outwardmovement of said wedge plates and means for returning the plates to normal or released position. 7

5. A draft gear comprising a plurality of sets of intercalated friction plates, followers adapted to engage against opposite outer v ends of said sets of plates, a plurality of pairs of wedge plates engaging their inner longltudinal sides with said fiction plates and provided on their outer longitudinal sides with inclined faces and coupled, respectively, with said followers so as to move lengthwise therewith, thrust members surrounding said pairs of wedge plates and each thrust member provided with inclined faces engaging with the inclined faces of one pair of wedge plates, a thrust spring surrounding said friction plates and engaging its opposite ends with said thrust members and operating constantly to force the sameapart, said thrust members being provided on their inner edges with notches, and said wedge plates being provided on their outer'sides with longitudinal ribs arranged in said notches, respectively,

and with lugs adapted to engage with the inner faces of said thrust members and means for returning the plates to normal or released position.

6. A draft gear comprising a plurality of sets of intercalated friction plates each of which is provided with inwardly facing shoulders, followers adapted to engage with the outer ends of said sets of plates, wedge plates coupled with said followers and engaging with the outer sides of said sets of plates, thrust members having wedging engagement with said wedge plates and adapted to engage their outer sides with said shoulders of the friction plates, and a spring surrounding said friction plates and engaging with said thrust members.

7. A draft gear comprising a plurality of sets of intercalated friction plates, followers adapted to bear against the outer ends of said sets of friction plates, respectively, wedge plates engaging with the longitudinal sides of said friction plates, thrust members having wedging engagement with said wedge plates, a thrust spring interposed between said thrust members, means for coupling said wedge plates with said followers, release spring means interposed between said followers and means for returning the plates to nor mal or released position. 1

' 8. A draft gear comprising a plurality of sets of intercalated friction plates, followers adapted to bear against the outer ends of said sets of friction plates, respectively, wedge plates engaging with the longitudinal sides of said friction plates, thrust members having wedging engagement with said wedge plates, a thrust spring interposed between said thrust members, retaining plates engaging with the inner sides of said followers and provided with flanges overhanging said wedge plates and also provided with spring seats, release springs engaging opposite ends with the spring seats of the retaining plates on the followers and means for returning the plates to normal or released position;

9. In a draft gear, a pair of followers, in-

tercalated friction plates between said followers, a spring seat member extending about each end of said friction plates, wedge faces on said members, a plurality of laterally movable wedge elements at each end of said gear cooperating with said faces for constituting the sole wedging means for creating lateral pressure on said plates during the compres-' sion of said gear, and springs for resisting the lnward movements of sald members when said gear is compressed.

JOSEPH M. HALL. 

